Our research interests are in protein conformational dynamics, protein-solvent interactions, and the characterization of dynamically distinct substructures in proteins. We employ a number of techniques to explore protein dynamics including 2H NMR, and hydrogen isotope exchange measured by 1H 2D COSY NMR and Electrospray Ionization Mass Spectrometry (ESI-MS). Another source of information about protein flexibility is the Debye-Waller factor or B-factor determined by X-ray crystallography, which is a measure of the atomic mean square displacement of atoms. We are interested in modeling atomic B-factors and in understanding the various contributions to B-factors from internal protein motions, rigid-body motions of protein molecules in the crystal, as well as the effects of crystal lattice contacts on B-factors.
Figure 1: B-factors for sialidase (3sil.pdb) calculated with GNM-TLS model (red) compared to experimental values (blue) with residuals (green) (corr. coeff. = 0.83).
A second area of interest is the development of protein analytical methods including the development of novel chromatographic stationary phases for the separation of peptides, proteins, and metabolites in collaboratory with Dr. Mahinda Gangoda. We also conduct proteomics studies of multiple sclerosis using mass spectrometry, 2D HPLC, and various electrophoresis techniques including western blotting in collaboration with Dr. Ernest Freeman (Dept. of Biological Sciences) and Dr. Jennifer McDonough (Dept. of Biological Sciences) to understand the role of mitochondrial dysfunction and oxidative damage in multiple sclerosis.
Figure 2: 4-propylaminomethyl benzoic acid (PAMBA) bonded silica - a versatile zwiterionic HPLC stationary phase which operates with high efficiency in cationic and anionic separation modes shown here separating (1) histidine, (2) lysine, and (3) arginine.